CSA (Canadian Standards Association) is an organization based out of Canada that is very similar to UL (Underwriters Laboratory) in the USA. Like UL, CSA provides two primary services. First, they develop Canada's minimum standards for the design, construction, and safety of a wide variety of products that are commercially sold in that country. These standards are completely voluntary and not a requirement for all products sold in Canada. Second, CSA acts as an NRTL (Nationally Recognized Testing Laboratory), which is essentially a 3rd party testing agency that has their own engineers/inspectors test and evaluate a product to ensure that it meets the requirements established in the applicable standards document for the primary market where the products are sold. In Grizzly's case, this is the USA and Canada, so many Grizzly machines are certified (usually by CSA, UL, or ETL) to meet both CSA (Canada) and UL (USA) standards.
So, although CSA produces their own standards, any NRTL (such as UL, ETL, TUV, etc.) can also certify the same products to the CSA standards. The reason why one NRTL is used over another typically just boils down to a business decision by the company paying the NRTL to test/evaluate their products. An important part of any NRTL certification, besides the initial testing/evaluation, is the ongoing compliance requirements necessary to maintain the certification. This involves both regular and random product checks by the NRTL's inspectors or engineers at the factory or on the consumer level.